Device and method for detecting volatile sulfide of viscose fiber

Abstract

The invention discloses a specific device and a method for enabling volatile sulfides in viscose fibers to escape when meeting hot water by using the device and qualitatively and quantitatively detecting the volatile sulfides by using a gas chromatograph. The method comprises the following steps: wetting a viscose fiber sample with water, dehydrating the viscose fiber sample to a preset liquid carrying rate, placing the viscose fiber sample in a sealed bottle, heating in a water bath, and filling a gas collection bag with generated volatile sulfides to obtain gas to be detected. And analyzing by using a gas chromatograph with a sulfur chemiluminescence detector. And comparing the gas chromatogram of the to-be-detected gas with the gas chromatograms of the hydrogen sulfide and carbon disulfide standard samples to determine the components of the volatile sulfides in the samples. And calculating the concentrations of hydrogen sulfide and carbon disulfide generated by the viscose fiber at specific water bath temperature and heating time according to the chromatographic peak area of the gas to be detected by using a pre-established standard curve of hydrogen sulfide and carbon disulfide.

Description

Technical Field

[0001] The invention relates to the field of viscose fiber detection, in particular to a method for qualitatively and quantitatively detecting volatile sulfides generated by viscose fibers and products thereof when they are exposed to hot water by using a specific device and a gas chromatograph. Background Art

[0002] Viscose fiber has been widely used in the field of nonwoven fabrics in recent years due to its excellent moisture absorption and breathability and relatively cheap price, such as cotton soft wipes, wet wipes, masks, protective clothing, etc. However, the odor problem of viscose nonwoven fabrics has gradually been exposed. Viscose nonwoven fabrics produce an unpleasant odor when exposed to hot water, which affects the further application of viscose fiber in the field of nonwoven fabrics. A large number of studies have shown that the odor of viscose fiber comes from the residual sulfide in the fiber preparation process, especially carbon disulfide and hydrogen sulfide gas. In the viscose preparation process, cellulose pulp is alkalized and reacts with the introduced carbon disulfide to form cellulose xanthate, which is easy to dissolve in alkali to form a spinning solution. When cellulose xanthate is ejected from the spinneret and encounters a coagulation bath containing sulfuric acid, it is reduced to cellulose, precipitated into silk, and hydrogen sulfide and carbon disulfide are released at the same time. Hydrogen sulfide and carbon disulfide both have an unpleasant odor and are considered to be the main source of the odor of viscose fiber when it is exposed to hot water. Both of them evaporate from the fibers, causing mild discomfort to the human sense of smell, and severe irritation symptoms such as contact headaches, dizziness, and nausea.

[0003] Volatile sulfide has become one of the key factors affecting the quality of nonwoven viscose fibers. Quality control starts with testing. The detection method of volatile sulfide in viscose fiber is particularly important for the viscose fiber and its products industry. However, the industry still lacks a detection method for volatile sulfide in viscose fiber. There is only a detection method for the total residual sulfur content in the fiber, such as the industry standard FZ / T 50014-2008 "Viscose Sulfur Content". This method is not suitable for evaluating the volatility of viscose fiber sulfide (which determines the size of fiber odor). In view of this, a method that can accurately evaluate the generation of volatile sulfide in viscose fibers and their products when exposed to hot water is urgently needed in the industry. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for detecting volatile sulfide in viscose fiber.

[0005] In order to solve the above technical problems, the present invention provides a device for collecting volatile sulfide of viscose fiber, which is composed of a sealed glass bottle (sealed glass bottle of predetermined volume), a thermostatic water bath and a gas collecting bag (gas collecting bag of predetermined volume); the sealed glass bottle is connected to a funnel with a valve filled with clean water and a conduit with a valve connected to the gas collecting bag. Figure 1 shown.

[0006] As an improvement of the device for collecting volatile sulfides of viscose fibers of the present invention: the volume of the sealed glass bottle is 0.5L to 2.5L; the volume of the air collecting bag is 0.5L to 2.5L.

[0007] The present invention also provides a method for detecting volatile sulfide of viscose fiber, including a method for producing volatile sulfide of viscose fiber and an instrumental analysis method for volatile sulfide of viscose fiber.

[0008] The method for producing the viscose fiber volatile sulfide is specifically as follows:

[0009] Take the viscose fiber to be tested as a sample (the sampling amount of the viscose fiber to be tested is 10g to 100g), put it in pure water to completely wet it, wring it to a predetermined liquid ratio (i.e., the mass percentage of water to fiber), and obtain a wet fiber sample. After tearing the wet fiber sample apart, put it in a sealed glass bottle and seal it. Then put the sealed glass bottle in a water bath at a predetermined temperature (the water surface completely covers the sample). After the water bath is heated for a predetermined time, open the valve of the funnel and the valve of the gas collecting bag conduit respectively, fill the bottle with water, and make the volatile sulfide gas in the sealed glass bottle fill into the gas collecting bag to a predetermined volume, and obtain the gas to be tested;

[0010] The liquid carrying rate is 200% to 350%;

[0011] The water bath temperature is 50℃~100℃, and the water bath heating time is ≥5min; the volume of the gas to be tested filled in the gas collecting bag is ≥100mL.

[0012] The goal of water bath heating is to make the volatile sulfide in the viscose fiber escape from the fiber so as to collect and detect these volatile sulfide components.

[0013] The instrumental analysis method of volatile sulfide of viscose fiber is specifically as follows:

[0014] The volatile sulfides to be tested are analyzed by using a gas chromatograph and a chromatographic analysis method (a gas chromatograph with a specific type of detector and a specific chromatographic analysis method); when the absolute value of the difference between the retention time corresponding to two chromatographic peaks in the gas chromatogram of the volatile sulfides to be tested and the retention time of the standard samples of hydrogen sulfide and carbon disulfide is ≤0.1min, they are determined to be volatile hydrogen sulfide and carbon disulfide in the sample; and the volume concentration of hydrogen sulfide and carbon disulfide volatilized from the sample within a predetermined water bath heating time is obtained by using the chromatographic peak areas corresponding to hydrogen sulfide and carbon disulfide in the sample chromatogram and the standard curve equations of hydrogen sulfide and carbon disulfide established in advance; and the mass concentration of hydrogen sulfide and carbon disulfide volatilized from the fiber within the water bath heating time is obtained according to the volume concentration of hydrogen sulfide and carbon disulfide in the gas to be tested, the volume of the sealed glass bottle and the mass of the viscose fiber sample;

[0015] The detection method of the gas to be tested is gas chromatography, and the detector is a sulfur chemiluminescence detector (SCD detector);

[0016] The chromatographic analysis method is as follows: the initial temperature of the chromatographic column is 20°C to 50°C, and the temperature is raised to above 100°C; the carrier gas is helium or nitrogen, and the carrier gas flow rate is 0.3mL / min to 1.0mL / min; the injection volume is 0.2mL to 2.0mL / min;

[0017] The calculation method of the mass concentration of hydrogen sulfide and carbon disulfide is: the mass concentration of hydrogen sulfide or carbon disulfide (μg / g) = the volume concentration of hydrogen sulfide or carbon disulfide in the gas to be tested (mg / m 3 )×the volume of the sealed glass bottle (L)÷the mass of the fiber sample (g).

[0018] In the present invention, the gas chromatography analysis method is preferably as follows: the chromatographic column specification is 50m×200μm×0.5μm capillary column; the carrier gas is nitrogen; the flow rate is 0.5mL / min; the programmed temperature is increased from the initial temperature of 35°C to 220°C at 5°C / min; and the injection volume is 1mL.

[0019] The technical solution of the present invention includes a device for collecting volatile sulfides of viscose fibers, a method for producing volatile sulfides of viscose fibers and an instrumental analysis method for volatile sulfides of viscose fibers.

[0020] The device and the testing method of the present invention are simple and easy to implement, and can accurately evaluate the amount of volatile sulfide produced when viscose fibers and products thereof are exposed to hot water for a certain period of time.

[0021] The present invention is specifically achieved through the following technical solutions:

[0022] (1) Establishing standard curves for hydrogen sulfide and carbon disulfide

[0023] a. Take known hydrogen sulfide and carbon disulfide standard gases of different concentrations, analyze them using a gas chromatograph, and obtain the gas chromatograms of hydrogen sulfide and carbon disulfide standard gases respectively.

[0024] b. Use the concentration of hydrogen sulfide and carbon disulfide standard gases as the horizontal axis and the gas chromatographic peak area as the vertical axis to draw a graph and perform linear fitting to obtain a linear regression equation, that is, the standard curve equation of hydrogen sulfide and carbon disulfide.

[0025] c. Take 10g-100g of the viscose fiber sample to be tested, place it in pure water to completely wet it, and twist it by hand to a predetermined liquid rate of 200-350% to obtain a wet fiber sample. Tear the wet fiber sample apart and place it in a 0.5L-2.5L sealed glass bottle and then place the sealed glass bottle in a 50℃-100℃ water bath (the water surface completely covers the sample). After heating in the water bath for more than 5 minutes, open the valve of the funnel and the valve of the gas collecting bag catheter respectively, and fill the bottle with water to allow the volatile sulfide gas in the sealed glass bottle to be filled into the gas collecting bag by at least 100mL to obtain the gas to be tested.

[0026] d. Use a gas chromatograph to analyze the gas to be tested and obtain a gas chromatogram of the gas to be tested.

[0027] e. Compare the gas chromatogram of the gas to be tested with the gas chromatograms of hydrogen sulfide and carbon disulfide standard gases. If the absolute value of the difference between the retention time corresponding to two chromatographic peaks in the gas chromatogram of the gas to be tested and the retention time of hydrogen sulfide and carbon disulfide standard gases is ≤0.1min, it is determined that the two chromatographic peaks in the gas chromatogram of the test gas are hydrogen sulfide and carbon disulfide.

[0028] f. According to the chromatographic peak areas of hydrogen sulfide and carbon disulfide in the gas chromatogram of the gas to be tested, the standard curve equations of hydrogen sulfide and carbon disulfide are substituted to obtain the volume concentrations of hydrogen sulfide and carbon disulfide in the gas to be tested.

[0029] g. According to the volume concentration of hydrogen sulfide and carbon disulfide in the gas to be tested, the volume of the sealed glass bottle and the mass of the viscose fiber sample, the mass concentration of hydrogen sulfide and carbon disulfide volatilized from the fiber during the water bath heating time is calculated. That is, the mass concentration of hydrogen sulfide or carbon disulfide (μg / g) = the volume concentration of hydrogen sulfide or carbon disulfide in the gas to be tested (mg / m 3 )×the volume of the sealed glass bottle (L)÷the mass of the fiber sample (g).

[0030] The gas chromatograph in steps a and d has a detector type of sulfur chemiluminescence detector (SCD detector); the carrier gas is helium or nitrogen; the flow rate is 0.3 mL / min-1.0 mL / min; the initial temperature of the chromatographic column is 20°C-50°C, the heating rate is 5°C / min, and the temperature is raised to at least 100°C; and the injection volume is 0.2 mL-2.0 mL.

[0031] The present invention has the following technical advantages:

[0032] 1. The present invention is the first to establish a device for producing and collecting volatile sulfides of viscose fibers. The device is simple, convenient and inexpensive;

[0033] 2. The present invention is a method for detecting volatile sulfides in viscose fibers based on sulfur chemiluminescence gas chromatography. The method is reliable and the detection results are highly accurate.

[0034] In summary, the present invention discloses a specific device and a method for qualitatively and quantitatively detecting the volatile sulfide in viscose fiber by using the device to make the volatile sulfide in viscose fiber escape when it encounters hot water. The viscose fiber sample is moistened with water and then dehydrated to a predetermined liquid carrying rate, placed in a sealed bottle and heated in a water bath, and then the generated volatile sulfide is filled into a gas collecting bag to obtain the gas to be tested. The gas is analyzed by using a gas chromatograph with a sulfur chemiluminescence detector. The gas chromatogram of the gas to be tested is compared with the gas chromatogram of the standard sample of hydrogen sulfide and carbon disulfide to determine the composition of the volatile sulfide in the sample. The standard curves of hydrogen sulfide and carbon disulfide established in advance are used to calculate the concentration of hydrogen sulfide and carbon disulfide generated by the viscose fiber at a specific water bath temperature and heating time according to the chromatographic peak area of ​​the gas to be tested.

[0035] The device and method for detecting volatile sulfide of viscose fiber established by the present invention solve the problem of difficulty in qualitative and quantitative analysis of odor substances in viscose fiber products in the viscose products industry; the method of the present invention is simple and rapid to operate, the experimental results are reliable, the accuracy is high, and it can be used for quality control and evaluation of viscose products. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0037] Figure 1 is a schematic diagram of a device for collecting volatile sulfide of viscose fiber;

[0038] Figure 2 It is the gas chromatogram of hydrogen sulfide and carbon disulfide standard gas substances;

[0039] Figure 3 is a gas chromatogram of volatile sulfides of viscose fiber in Example 1 of the present invention;

[0040] Figure 4 is a gas chromatogram of volatile sulfides of viscose fiber in Example 2 of the present invention;

[0041] Figure 5 It is the gas chromatogram of the volatile sulfide of the viscose fiber in Example 3 of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0043] Example 1: 1# viscose staple fiber sample, produced by a well-known viscose fiber production enterprise in Xinjiang Uygur Autonomous Region. The viscose fiber sample was subjected to the following operations in sequence:

[0044] Take 30g of the viscose fiber sample to be tested, place it in pure water to completely wet it, and twist it by hand to a predetermined liquid rate of 272% to obtain a wet fiber sample. Tear the wet fiber sample apart and place it in a 2.0L sealed glass bottle and then place the sealed glass bottle in a 55°C water bath (the water surface completely covers the sample). After heating in the water bath for 20 minutes, open the valve of the funnel and the valve of the gas collecting bag catheter respectively, and fill water into the bottle to allow the volatile sulfide gas in the sealed glass bottle to fill about 1L of the gas collecting bag to obtain the gas to be tested.

[0045] The gas to be tested was analyzed by Agilent 7890B gas chromatograph (with sulfur chemiluminescence detector), with the starting temperature at 35°C and the temperature rising to 160°C at a rate of 5°C / min. The chromatographic column was Agilent PONA column with specifications of 50m×200μm×0.5μm. The carrier gas was nitrogen, the carrier gas flow rate was 0.5mL / min, and the injection volume was 0.25mL.

[0046] Analysis results: The gas chromatogram of the test gas of sample 1# is obtained, such as Figure 3 Compare the gas chromatogram of the gas to be tested with the gas chromatogram of the standard gas of hydrogen sulfide and carbon disulfide (as shown in Figure 2 The gas chromatogram of the gas to be tested has two chromatographic peaks with retention times of 3.669min and 9.954min, and the absolute values ​​of the differences between the retention times of the standard gases of hydrogen sulfide and carbon disulfide (3.659min and 9.936min) are 0.010 and 0.018min, respectively, both less than ≤0.1min. It can be determined that the chromatographic peaks at the retention times of 3.669min and 9.954min are hydrogen sulfide and carbon disulfide, respectively.

[0047] According to the peak area of ​​hydrogen sulfide and carbon disulfide in the gas chromatogram of the gas to be tested, the volume concentrations of hydrogen sulfide and carbon disulfide in the gas to be tested are obtained to be 0.0562 mg / m3 and 0.1179 mg / m 3 The calculated mass concentrations of hydrogen sulfide and carbon disulfide volatilized in a 55°C water bath within 20 minutes were 0.004μg / g and 0.008μg / g.

[0048] Example 2: 2# viscose staple fiber sample, produced by a well-known viscose fiber production enterprise in Tangshan. The viscose fiber sample was subjected to the following operations in sequence:

[0049] Take 15g of the viscose fiber sample to be tested, place it in pure water to completely wet it, and twist it by hand to a predetermined liquid rate of 235% to obtain a wet fiber sample. Tear the wet fiber sample apart and place it in a 1.0L sealed glass bottle and seal it. Then place the sealed glass bottle in a 70°C water bath (the water surface completely covers the sample). After heating in the water bath for 10 minutes, open the valve of the funnel and the valve of the gas collecting bag catheter respectively, and fill water into the bottle to allow the volatile sulfide gas in the sealed glass bottle to fill about 0.25L of the gas collecting bag to obtain the gas to be tested.

[0050] The gas to be tested was analyzed using an Agilent 7890B gas chromatograph (equipped with a sulfur chemiluminescence detector) (chromatographic conditions were the same as in Example 1), and a gas chromatogram of the gas to be tested of sample 2# was obtained (as shown in FIG. Figure 4 shown).

[0051] The gas chromatogram of the gas to be tested is compared with the gas chromatograms of hydrogen sulfide and carbon disulfide standard gases (as shown in 2). The absolute values ​​of the differences between the retention times corresponding to the two chromatographic peaks with retention times of 3.663min and 9.955min in the gas chromatogram of the gas to be tested and the retention times of hydrogen sulfide and carbon disulfide standard gases are 0.004 and 0.019min, respectively, both of which are less than ≤0.1min. It can be determined that the chromatographic peaks at the retention times of 3.663min and 9.955min of the test gas are hydrogen sulfide and carbon disulfide, respectively.

[0052] According to the peak areas of hydrogen sulfide and carbon disulfide in the gas chromatogram of the gas to be tested, the volume concentrations of hydrogen sulfide and carbon disulfide in the gas to be tested were obtained to be 0.1120 mg / m 3 and 0.4957mg / m 3 . It was calculated that the mass concentrations of hydrogen sulfide and carbon disulfide volatilized in a 70°C water bath within 10 minutes were 0.007μg / g and 0.033μg / g.

[0053] Example 3: 3# viscose staple fiber sample, produced by Jiangxi branch of a well-known domestic viscose fiber production enterprise. The viscose fiber sample was subjected to the following operations in sequence:

[0054] Take 65g of the viscose fiber sample to be tested, place it in pure water to completely wet it, and twist it by hand to a predetermined liquid rate of 305% to obtain a wet fiber sample. Tear the wet fiber sample apart and place it in a 2.0L sealed glass bottle and then place the sealed glass bottle in a 90°C water bath (the water surface completely covers the sample). After heating in the water bath for 10 minutes, open the valve of the funnel and the valve of the gas collecting bag catheter respectively, and fill water into the bottle to allow the volatile sulfide gas in the sealed glass bottle to fill about 1.5L of the gas collecting bag to obtain the gas to be tested.

[0055] The gas to be tested was analyzed by Agilent 7890B gas chromatograph (with sulfur chemiluminescence detector), with the starting temperature at 35°C and the temperature rising to 160°C at a rate of 5°C / min. The chromatographic column was Agilent PONA column with specifications of 50m×200μm×0.5μm. The carrier gas was nitrogen, the carrier gas flow rate was 0.5mL / min, and the injection volume was 1mL.

[0056] Analysis results: The gas chromatogram of the gas to be tested of sample 3# is obtained, such as Figure 5 Compare the gas chromatogram of the gas to be tested with the gas chromatogram of the standard gas of hydrogen sulfide and carbon disulfide (as shown in Figure 2 The gas chromatogram of the gas to be tested has two chromatographic peaks with retention times of 3.673min and 9.957min, and the absolute values ​​of the differences between the retention times of the standard gases of hydrogen sulfide and carbon disulfide (3.659min and 9.936min) are 0.014 and 0.021min, respectively, both of which are less than ≤0.1min. It can be determined that the chromatographic peaks at the retention times of 3.673min and 9.957min are hydrogen sulfide and carbon disulfide, respectively.

[0057] According to the peak areas of hydrogen sulfide and carbon disulfide in the gas chromatogram of the gas to be tested, the volume concentrations of hydrogen sulfide and carbon disulfide in the gas to be tested were obtained to be 0.3068 mg / m 3 and 0.8216mg / m 3 The calculated mass concentrations of hydrogen sulfide and carbon disulfide volatilized in a 90°C water bath within 10 minutes were 0.009 μg / g and 0.025 μg / g.

[0058] Finally, it should be noted that although the above are only some specific embodiments of the present invention, some modifications or improvements can be made on the basis of the present invention, which is obvious to those skilled in the art. Therefore, all the variations directly derived or associated with the contents disclosed in the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A device for collecting volatile sulfides of viscose fibers, characterized in that: The invention is composed of a sealed glass bottle, a water bath with adjustable temperature and an air collecting bag; the sealed glass bottle is externally connected to a funnel with a valve filled with clean water and a catheter with a valve connected to the air collecting bag.

2. The device for collecting volatile sulfide of viscose fiber according to claim 1, characterized in that: The volume of the sealed glass bottle is 0.5L~2.5L; the volume of the air collecting bag is 0.5L~2.5L.

3. A method for detecting volatile sulfide in viscose fiber, characterized in that: The invention comprises a method for producing volatile sulfide of viscose fiber and an instrumental analysis method for volatile sulfide of viscose fiber.

4. The method for detecting volatile sulfide in viscose fiber according to claim 3, characterized in that: The method for producing the viscose fiber volatile sulfide is: Take the viscose fiber to be tested as a sample, place it in pure water to completely wet it, and wring it to a predetermined liquid ratio to obtain a wet fiber sample. Tear the wet fiber sample apart and place it in a sealed glass bottle and seal it. Then place the sealed glass bottle in a water bath at a predetermined temperature. After heating in the water bath for a predetermined time, open the valve of the funnel and the valve of the gas collecting bag catheter respectively, fill the bottle with water, and allow the volatile sulfide gas in the sealed glass bottle to fill into the gas collecting bag to a predetermined volume to obtain the gas to be tested.

5. The method for detecting volatile sulfide in viscose fiber according to claim 4, characterized in that: The liquid carrying rate is 200% to 350%.

6. The method for detecting volatile sulfide in viscose fiber according to claim 5, characterized in that: The water bath temperature is 50℃~100℃, and the water bath heating time is ≥5min; the volume of the gas to be tested filled in the gas collecting bag is ≥100mL.

7. The method for detecting volatile sulfide in viscose fiber according to any one of claims 3 to 6, characterized in that: The instrumental analysis method of the volatile sulfide of the viscose fiber is: The volatile sulfides to be tested are analyzed by using a gas chromatograph and a chromatographic analysis method; when the absolute value of the difference between the retention time corresponding to two chromatographic peaks in the gas chromatogram of the volatile sulfides to be tested and the retention time of the standard samples of hydrogen sulfide and carbon disulfide is ≤0.1min, they are determined to be volatile hydrogen sulfide and carbon disulfide in the sample; and the volume concentration of hydrogen sulfide and carbon disulfide volatilized from the sample within a predetermined water bath heating time is calculated using the chromatographic peak areas corresponding to hydrogen sulfide and carbon disulfide in the sample chromatogram and the standard curve equations of hydrogen sulfide and carbon disulfide established in advance; and the mass concentration of hydrogen sulfide and carbon disulfide volatilized from the fiber within the water bath heating time is calculated based on the volume concentration of hydrogen sulfide and carbon disulfide in the gas to be tested, the volume of the sealed glass bottle and the mass of the viscose fiber sample.

8. The method for detecting volatile sulfide in viscose fiber according to claim 7, characterized in that: The detection method of the gas to be tested is gas chromatography, and the detector is a sulfur chemiluminescence detector.

9. The method for detecting volatile sulfide in viscose fiber according to claim 7 or 8, characterized in that: The chromatographic analysis method is as follows: the initial temperature of the chromatographic column is 20°C to 50°C, and the temperature is raised to above 100°C; the carrier gas is helium or nitrogen, and the carrier gas flow rate is 0.3mL / min to 1.0mL / min; the injection volume is 0.2mL to 2.0mL / min.

10. The method for detecting volatile sulfide in viscose fiber according to claim 9, characterized in that: The calculation method of mass concentration of hydrogen sulfide and carbon disulfide is: mass concentration of hydrogen sulfide or carbon disulfide (μg / g) = volume concentration of hydrogen sulfide or carbon disulfide in the gas to be tested (mg / m 3 )×the volume of the sealed glass bottle (L)÷the mass of the fiber sample (g).

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